100 research outputs found
The short-duration GRB 050724 host galaxy in the context of the long-duration GRB hosts
We report optical and near-infrared broad band observations of the
short-duration GRB 050724 host galaxy, used to construct its spectral energy
distribution (SED). Unlike the hosts of long-duration gamma-ray bursts (GRBs),
which show younger stellar populations, the SED of the GRB 050724 host galaxy
is optimally fitted with a synthetic elliptical galaxy template based on an
evolved stellar population (age ~2.6 Gyr). The SED of the host is difficult to
reproduce with non-evolving metallicity templates. In contrast, if the short
GRB host galaxy metallicity enrichment is considered, the synthetic templates
fit the observed SED satisfactorily. The internal host extinction is low (A_v
\~< 0.4 mag) so it cannot explain the faintness of the afterglow. This short
GRB host galaxy is more massive (~5x10^10 Mo) and luminous (~1.1 L*) than most
of the long-duration GRB hosts. A statistical comparison based on the ages of
short- and long-duration GRB host galaxies strongly suggests that
short-duration GRB hosts contain, on average, older progenitors. These findings
support a different origin for short- and long-duration GRBs.Comment: A&A in pres
Two transitional type Ia supernovae located in the Fornax cluster member NGC 1404: SN 2007 on and SN 2011iv
We present an analysis of ultraviolet (UV) to near-infrared observations of the fast-declining Type Ia supernovae (SNe Ia) 2007on and 2011iv, hosted by the Fornax cluster member NGC 1404. The B-band light curves of SN 2007on and SN 2011iv are characterised by Δm15 (B) decline-rate values of 1.96 mag and 1.77 mag, respectively. Although they have similar decline rates, their peak B- and H-band magnitudes differ by ~ 0.60 mag and ~0.35 mag, respectively. After correcting for the luminosity vs. decline rate and the luminosity vs. colour relations, the peak B-band and H-band light curves provide distances that differ by ~ 14% and ~ 9%, respectively. These findings serve as a cautionary tale for the use of transitional SNe Ia located in early-type hosts in the quest to measure cosmological parameters. Interestingly, even though SN 2011iv is brighter and bluer at early times, by three weeks past maximum and extending over several months, its B - V colour is 0.12 mag redder than that of SN 2007on. To reconcile this unusual behaviour, we turn to guidance from a suite of spherical one-dimensional Chandrasekhar-mass delayed-detonation explosion models. In this context, 56Ni production depends on both the so-called transition density and the central density of the progenitor white dwarf. To first order, the transition density drives the luminosity-width relation, while the central density is an important second-order parameter. Within this context, the differences in the B - V colour evolution along the Lira regime suggest that the progenitor of SN 2011iv had a higher central density than SN 2007on.Instituto de Astrofísica de La PlataFacultad de Ciencias Astronómicas y Geofísica
VizieR Online Data Catalog: BVRI LCs of type Ib supernova iPTF13bvn (Folatelli+, 2016)
We obtained deep imaging of the field of iPTF13bvn ~740 days after explosion using HST through Cycle 22 programs GO-13684 and GO-13822. Program GO-13684 was executed between 2015 June 26.37 and 26.60 (UT dates are used herein) with the Wide Field Camera 3 (WFC3) UVIS channel. Program GO-13822 comprised observations obtained on 2015 June 30.63 with WFC3/UVIS (F225W filter) and on June 30.90 UT with the Advanced Camera for Surveys (ACS; F814W filter). The supernova (SN) location in the pre- and post-explosion images was found by aligning them relative to a F555W image obtained through program GO-12888 with WFC3/UVIS on 2013 September 2.37 when the SN was still very bright. We also obtained BVRI imaging of iPTF13bvn until ~280 days with the Katzman Automatic Imaging Telescope (KAIT) and the 1m Nickel telescope at Lick Observatory (see table 3). Apparent magnitudes were first measured in the KAIT4 natural system and then transformed to the standard system using local calibrators and color terms as given in Table 4 of Ganeshalingam et al. (2010, J/ApJS/190/418)
LIGO/VIRGO G184098 : classifications of transients from the LSQ observations
Classification of the transients LSQ15bbb and LSQ15bbj from the LSQ observations. They are candidates in the G184098 error box
VizieR Online Data Catalog: SN 2007on and SN 2011iv light curves (Gall+, 2018)
Detailed optical and NIR light curves of SN 2007on obtained by the first phase of the Carnegie Supernova Project (CSP-I, 2004-2009; Hamuy et al., 2006PASP..118....2H) were published by Stritzinger et al. (2011, Cat. J/AJ/142/156).UV uvw2-, uvm2-, and uvw1-band imaging of both SN 2007on and SN 2011iv were obtained with Swift (+ UVOT). Photome- try of SN 2007on and SN 2011iv was computed following the method described in detail by Brown et al. (2014Ap&SS.354...89B), who use the calibration published by Breeveld et al. (2011, AIPCS, 1358, 373). The Swift UVOT images and photometry are also available as part of the Swift Optical Ultraviolet Supernova Archive (SOUSA; Brown et al. 2014Ap&SS.354...89B). Optical ugriBV-band imaging of SN 2007on and SN 2011iv was obtained with the Henrietta Swope 1.0m telescope (+ SITe3 direct CCD camera) located at the Las Campanas Observatory (LCO). The NIR YJH-band imaging of SN 2007on was obtained with the Swope (+ RetroCam) and the Irenee du Pont 2.5m (+ WIRC: Wide Field Infrared Camera) telescopes (Stritzinger et al., Cat. J/AJ/142/156), while in the case of SN 2011iv all NIR YJH-band imaging was taken with RetroCam attached to the Irenee du Pont telescope. The optical local sequence is calibrated relative to Landolt (1992AJ....104..372L) (BV) and Smith et al. (2002AJ....123.2121S) (ugri) standard-star fields observed over multiple photometric nights. The NIR J-band and H-band local sequences were calibrated relative to the Persson et al. (1998AJ....116.2475P) standard stars, while the Y- band local sequence was calibrated relative to standard Y-band magnitudes computed using a combination of stellar atmosphere models (Castelli & Kurucz, 2003, IAUSymp, 210, A20) with the J-Ks colours of the Persson et al. standard-star catalogue (Hamuy et al., 2006PASP..118....2H). (5 data files)
Two transitional type~Ia supernovae located in the Fornax cluster member NGC 1404: SN 2007on and SN 2011iv
We present an analysis of ultraviolet (UV) to near-infrared observations of the fast-declining Type Ia supernovae (SNe Ia) 2007on and 2011iv, hosted by the Fornax cluster member NGC 1404. The B-band light curves of SN 2007on and SN 2011iv are characterised by dm_15(B) decline-rate values of 1.96 mag and 1.77 mag, respectively. Although they have similar decline rates, their peak B- and H-band magnitudes differ by ~0.60 mag and ~0.35 mag, respectively. After correcting for the luminosity vs. decline rate and the luminosity vs. colour relations, the peak B-band and H-band light curves provide distances that differ by ~14% and ~9%, respectively. These findings serve as a cautionary tale for the use of transitional SNe Ia located in early-type hosts in the quest to measure cosmological parameters. Interestingly, even though SN 2011iv is brighter and bluer at early times, by three weeks past maximum and extending over several months, its B-V colour is 0.12 mag redder than that of SN 2007on. To reconcile this unusual behaviour, we turn to guidance from a suite of spherical one-dimensional Chandrasekhar-mass delayed-detonation explosion models. In this context, 56Ni production depends on both the so-called transition density and the central density of the progenitor white dwarf. To first order, the transition density drives the luminosity-width relation, while the central density is an important second-order parameter. Within this context, the differences in the B-V color evolution along the Lira regime suggests the progenitor of SN~2011iv had a higher central density than SN~2007on
VizieR Online Data Catalog: Follow-up photometry of M101 OT2015-1 (Blagorodnova+, 2017)
The location of M101-OT2015-1 has been serendipitously imaged by numerous telescopes and instruments over the last 15 years (from 2000 to 2015). Our best quality pre-discovery image (seeing of 0.55") is an r-band exposure at -3625 days pre-peak from the Canada-France-Hawaii Telescope (CFHT). The historical optical data for M101-OT was retrieved from the CFHT MegaPrime and CFHT12K/Mosaic, using single and combined exposures, Pan-STARRS-1/GPC1 (PS1), Isaac Newton Telescope/Wide Field Camera (INT/WFC), and Sloan Digital Sky Survey (SDSS) DR 10 (Ahn+ 2014, see V/147). Unfortunately, there are no HST images covering the location of the source. Post-discovery optical magnitudes were obtained from the reported followup astronomer's telegrams (ATels), Liverpool Telescope (LT), the Nordic Optical Telescope (NOT), and the Palomar P48 and P60 telescopes. The infrared data were retrieved from CFHT/WIRCam, UKIRT/WFCAM, and the Spitzer Infrared Array Camera in 3.6 and 4.5um as part of the SPitzer InfraRed Intensive Transients Survey (SPIRITS) (Kasliwal+, 2017ApJ...839...88K). Details of pre-discovery photometry and post-discovery optical photometry may be found in the Appendices Tables 1 and 2, respectively. We obtained spectra of M101-OT using a range of facilities in 2015 Feb-Jul. (3 data files)
Two Chromogranin A-Derived Peptides Induce Calcium Entry in Human Neutrophils by Calmodulin-Regulated Calcium Independent Phospholipase A2
Background: Antimicrobial peptides derived from the natural processing of chromogranin A (CgA) are co-secreted with catecholamines upon stimulation of chromaffin cells. Since PMNs play a central role in innate immunity, we examine responses by PMNs following stimulation by two antimicrobial CgA-derived peptides. Methodology/Principal Findings: PMNs were treated with different concentrations of CgA-derived peptides in presence of several drugs. Calcium mobilization was observed by using flow cytometry and calcium imaging experiments. Immunocytochemistry and confocal microscopy have shown the intracellular localization of the peptides. The calmodulin-binding and iPLA2 activating properties of the peptides were shown by Surface Plasmon Resonance and iPLA2 activity assays. Finally, a proteomic analysis of the material released after PMNs treatment with CgA-derived peptides was performed by using HPLC and Nano-LC MS-MS. By using flow cytometry we first observed that after 15 s, in presence of extracellular calcium, Chromofungin (CHR) or Catestatin (CAT) induce a concentration-dependent transient increase of intracellular calcium. In contrast, in absence of extra cellular calcium the peptides are unable to induce calcium depletion from the stores after 10 minutes exposure. Treatment with 2-APB (2-aminoethoxydiphenyl borate), a store operated channels (SOCs) blocker, inhibits completely the calcium entry, as shown by calcium imaging. We also showed that they activate iPLA2 as the two CaM-binding factors (W7 and CMZ) and that the two sequences can be aligned with the two CaMbinding domains reported for iPLA2. We finally analyzed by HPLC and Nano-LC MS-MS the material released by PMNs following stimulation by CHR and CAT. We characterized several factors important for inflammation and innate immunity. Conclusions/Significance: For the first time, we demonstrate that CHR and CAT, penetrate into PMNs, inducing extracellular calcium entry by a CaM-regulated iPLA2 pathway. Our study highlights the role of two CgA-derived peptides in the active communication between neuroendocrine and immune systems
Risk factors for infections caused by carbapenem-resistant Enterobacterales: an international matched case-control-control study (EURECA)
Cases were patients with complicated urinary tract infection (cUTI), complicated intraabdominal (cIAI), pneumonia or bacteraemia from other sources (BSI-OS) due to CRE; control groups were patients with infection caused by carbapenem-susceptible Enterobacterales (CSE), and by non-infected patients, respectively. Matching criteria included type of infection for CSE group, ward and duration of hospital admission. Conditional logistic regression was used to identify risk factors. Findings Overall, 235 CRE case patients, 235 CSE controls and 705 non-infected controls were included. The CRE infections were cUTI (133, 56.7%), pneumonia (44, 18.7%), cIAI and BSI-OS (29, 12.3% each). Carbapenemase genes were found in 228 isolates: OXA-48/like, 112 (47.6%), KPC, 84 (35.7%), and metallo-beta-lactamases, 44 (18.7%); 13 produced two. The risk factors for CRE infection in both type of controls were (adjusted OR for CSE controls; 95% CI; p value) previous colonisation/infection by CRE (6.94; 2.74-15.53; <0.001), urinary catheter (1.78; 1.03-3.07; 0.038) and exposure to broad spectrum antibiotics, as categorical (2.20; 1.25-3.88; 0.006) and time-dependent (1.04 per day; 1.00-1.07; 0.014); chronic renal failure (2.81; 1.40-5.64; 0.004) and admission from home (0.44; 0.23-0.85; 0.014) were significant only for CSE controls. Subgroup analyses provided similar results. Interpretation The main risk factors for CRE infections in hospitals with high incidence included previous coloni-zation, urinary catheter and exposure to broad spectrum antibiotics
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